In 1992, a vascular disease was found in two fields of cultivar UC-15 garbanzo beans (Cicer arietinum). The fields were located on the central coast of California and Phialophora gregata was consistently isolated from the aboveground tissue in the host UC-15 plants. Diseased patches in the fields mimicked the more common Fusarium wilt with its discolored vascular tissue in the stems, but in these instances P. gregata was the sole fungus that grew out of the tissue after 5 to 8 days of incubation on isolation agar. Greenhouse pathogenicity tests yielded only minor symptoms whether a dip technique or stem puncture inoculations were used. In subsequent years it was noted that this disease was observed only in garbanzo fields where a pea crop (Pisum sativum) had been previously grown. Further isolation from small foot and root lesions of diseased field plants revealed that they were infected with Fusarium solani f. sp. pisi (Fsp) in addition to P. gregata. In greenhouse experiments with a combination of soilborne Fsp and/or stem inoculations with P. gregata, both pathogens infected the host. The symptoms from both pathogens, the strongest including occasional plant death, were similar to those observed in the fields. The effect was more than additive. Neither pathogen alone caused severe damage. In these tests Fsp was reisolated from root and foot cortical tissue along with P. gregata from stem vascular tissue near the top of the plants. Peas were an important crop along the central coast long before garbanzo beans were grown there. Fsp, a pathogen of both pea and garbanzo bean (1), has been known to attack garbanzos there since 1973 (2). The presence of yet another vascular disease of significance in this coastal area, besides those caused by Fusarium oxysporum f. sp. ciceri and Verticillium dahliae, has not been previously noted. Help in identification of P. gregata came from Diane Fogle, California Department of Food and Agriculture, Sacramento.
References: (1) J. M. Kraft. Plant Dis. Rep. 53:110, 1969. (2) F. V. Westerlund Jr., et al. Phytopathology 64:432, 1974.
